Thermal management system for gas turbine engine

ABSTRACT

A method of thermal management for a gas turbine engine comprising selectively positioning a valve to communicate a bypass flow into either an Environmental Control System (ECS) pre-cooler or an Air Oil Cooler (AOC) “peaker” through a common inlet.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/096,130, filed Apr. 28, 2011.

BACKGROUND

The present disclosure relates to a gas turbine engine, and inparticular, to a Thermal Management Systems (TMS) therefore.

Thermal Management Systems (TMS) include heat exchangers and associatedequipment that utilize a pressurized lubricant. During usage, thelubricant receives thermal energy. The heat of the lubricants in suchsystems has increased due to the use of larger electrical generators forincreased electrical power production and geared turbofans with largefan-drive gearboxes.

In one TMS, a duct is provided in a fan cowling through which a portionof the airstream is diverted, such that the lubricant is cooled by theducted airstream. The airstream that is diverted through the duct systemflows at least in part through an air-to-liquid heat exchanger which issized to provide adequate cooling for the most extreme “corner point”conditions (hot day, idle, hot fuel). These heat exchangers may requirerelatively large cross-sectional area ducts that may result inadditional drag.

Alternately, a base heat exchange that handles a significant portion ofthe mission points is combined with a so-called “peaker” heat exchangerto handle corner point conditions. One such TMS locates the “peaker” onthe engine fan case which also requires oil lines and valves to belocated along the fan case. This arrangement may require additionalauxiliary inlets and outlets which may also result in additional drag.

SUMMARY

A method of thermal management for a gas turbine engine according to anexample of the present disclosure includes selectively positioning avalve to communicate a bypass flow into either an Environmental ControlSystem (ECS) pre-cooler or an Air Oil Cooler (AOC) “peaker” through acommon inlet.

A further embodiment of the foregoing embodiments includes communicatingthe bypass airflow to the ECS pre-cooler during cold operations.

A further embodiment of any of the foregoing embodiments includescommunicating the bypass airflow to the AOC “peaker” during hotoperations.

A further embodiment of any of the foregoing embodiments includescommunicating an exhaust flow from the ECS pre-cooler or AOC “peaker”into a core engine.

A further embodiment of any of the foregoing embodiments includesproviding a compressor section, a turbine section, and a combustorsection in the core engine.

In a further embodiment of any of the foregoing embodiments, thecompressor section is configured to drive a core flow through the coreengine.

A further embodiment of any of the foregoing embodiments includescommunicating an exhaust flow from the ECS pre-cooler or AOC “peaker”overboard of the gas turbine engine.

A further embodiment of any of the foregoing embodiments includesdriving the bypass flow to the valve via a fan.

In a further embodiment of any of the foregoing embodiments, selectivelypositioning the valve includes rotating the valve.

In a further embodiment of any of the foregoing embodiments, selectivelypositioning the valve includes blocking bypass flow into both the ECSpre-cooler and the AOC “peaker.”

In a further embodiment of any of the foregoing embodiments, the valvecommunicates the bypass flow into either the ECS pre-cooler or the AOC“peaker” via first and second ducts, respectively.

In a further embodiment of any of the foregoing embodiments, selectivelypositioning the valve includes at least partially blocking bypass flowinto at least one of the first and second ducts.

In a further embodiment of any of the foregoing embodiments, selectivelypositioning the valve includes fully blocking bypass flow into at leastone of the first and second ducts.

In a further embodiment of any of the foregoing embodiments, selectivelypositioning the valve is accomplished by a control system.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiment. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a general schematic cross-section of a gas turbine engine;

FIG. 2 is a side partial sectional view of one embodiment of a thermalmanagement system;

FIG. 3 is a side partial phantom view of another non-limiting embodimentof a thermal management system;

FIG. 4 is a top view of the thermal management system of FIG. 3;

FIG. 5 is an expanded view of a valve arrangement for the thermalmanagement system in first position;

FIG. 6 is an expanded view of the valve arrangement for the thermalmanagement system in second position; and

FIG. 7 is an expanded view of the valve arrangement for the thermalmanagement system in third position.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbofan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. Alternative engines mightinclude an augmentor section (not shown) among other systems orfeatures. The fan section 22 drives air along a bypass flowpath whilethe compressor section 24 drives air along a core flowpath forcompression and communication into the combustor section 26 thenexpansion through the turbine section 28. Although depicted as aturbofan gas turbine engine in the disclosed non-limiting embodiment, itshould be understood that the concepts described herein are not limitedto use with turbofans as the teachings may be applied to other types ofturbine engines.

The engine 20 generally includes a low speed spool 30 and a high speedspool 32 mounted for rotation about an engine central longitudinal axisA relative to an engine static structure 36 via several bearing systems38. It should be understood that various bearing systems 38 at variouslocations may alternatively or additionally be provided.

The low speed spool 30 generally includes an inner shaft 40 thatinterconnects a fan 42, a low pressure compressor 44 and a low pressureturbine 46. The inner shaft 40 is connected to the fan 42 through ageared architecture 48 to drive the fan 42 at a lower speed than the lowspeed spool 30. The high speed spool 32 includes an outer shaft 50 thatinterconnects a high pressure compressor 52 and high pressure turbine54. A combustor 56 is arranged between the high pressure compressor 52and the high pressure turbine 54. The inner shaft 40 and the outer shaft50 are concentric and rotate about the engine central longitudinal axisA which is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 thenthe high pressure compressor 52, mixed with fuel and burned in thecombustor 56, then expanded over the high pressure turbine 54 and lowpressure turbine 46. The turbines 54, 46 rotationally drive therespective low speed spool 30 and high speed spool 32 in response to theexpansion.

With reference to FIG. 2, the gas turbine engine 20 is mounted to anengine pylon structure 60 within an engine nacelle assembly 62 as istypical of an aircraft designed for subsonic operation. The nacelleassembly 62 generally includes a core nacelle 64 and a fan nacelle 66. Athermal management system (TMS) 68 is at least partially integrated intothe nacelle assembly 62. It should be understood that although aparticular component arrangement is disclosed in the illustratedembodiment, various pylon structures and nacelle assemblies will benefitherefrom.

The TMS 68 includes a first heat exchanger HX1 and a second heatexchanger HX2 which are both in communication with the bypass flowthrough a common inlet 70. It should be understood that the heatexchangers HX1, HX2 may be air/fluid, or air/air heat exchangers.Air/fluid heat exchangers are typically utilized to cool engine fluidsto maintain low temperatures and air/air heat exchangers are typicallyutilized to cool high-temperature engine air for use in the aircraftcabin. In one non-limiting embodiment, the first heat exchanger HX1 isan Environmental Control System (ECS) pre-cooler and the second heatexchanger HX2 is an Air Oil Cooler (AOC) “peaker”. The ECS pre-coolermay be located within an engine strut fairing. In another disclosed,non-limiting embodiment, the first heat exchanger HX1 and/or the secondheat exchanger HX2 is suspended from a pylon 60′ within an engine strut36S (FIGS. 3 and 4) if the engine pylon 60′ mounts to the engine fancase 36F rather than the core case 36C.

A “Fan Air Modulating Valve” (FAMV) 72 in communication with the inlet70 selectively directs a portion of the bypass flow to either of theheat exchangers HX1, HX2. The FAMV 72 varies the bypass flow and therebyselectively controls the bypass air to the heat exchangers HX1, HX2. Theexhaust flow from the heat exchangers HX1, HX2 may then be dumped intothe core engine and/or overboard.

The ECS pre-cooler system is typically placed under high demand duringcold operation while the engine AOC “peaker” is typically utilizedduring hot operations which include “corner point” conditions such thatthe FAMV 72 selectively directs the bypass airflow as required in amutually exclusive manner. A duct 74 downstream of the FAMV 72 therebycommunicates a portion of bypass flow to either of the heat exchangersHX1, HX2.

The thermal management system (TMS) 68 thereby minimizes the number ofadditionally auxiliary inlets and outlets required in the propulsionsystem to integrate the AOC “peaker”. Additionally, the thermalmanagement system (TMS) 68 does not require engine powered fans to drivethe flow thru the AOC “peaker” to minimize or eliminate additional oillines and electrical supply/control lines to the fan case.

With reference to FIG. 5, the FAMV 72 is in communication with thecommon inlet 70 to selectively direct the portion of the bypass flow toeither of the heat exchangers HX1, HX2 through respective duct 76, 78(FIGS. 6, 7). In one non-limiting embodiment, the FAMV 72 includes avalve 80 which rotates about an axis of rotation B to selectively openthe respective duct 76, 78 to inlet 70. The FAMV 72 provides anessentially infinite position to control bypass flow into the respectiveduct 76, 78. That is, the FAMV 72 is positioned by a control system 82to, for example, partially open the respective duct 76, 78 and controlthe quantity of bypass flow thereto. The FAMV 72 may also be positionedto close both the respective ducts 76, 78 (FIG. 5).

It should be understood that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould also be understood that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, itshould be understood that steps may be performed in any order, separatedor combined unless otherwise indicated and will still benefit from thepresent invention.

The foregoing description is exemplary rather than defined by thelimitations within. Various non-limiting embodiments are disclosedherein, however, one of ordinary skill in the art would recognize thatvarious modifications and variations in light of the above teachingswill fall within the scope of the appended claims. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced other than as specifically described. For that reason,the appended claims should be studied to determine true scope andcontent.

What is claimed:
 1. A method of thermal management for a gas turbineengine comprising: selectively positioning a valve to communicate abypass flow into either an Environmental Control System (ECS) pre-cooleror an Air Oil Cooler (AOC) “peaker” through a common inlet.
 2. Themethod as recited in claim 1, further comprising: communicating anexhaust flow from the ECS pre-cooler or AOC “peaker” into a core engine.3. The method as recited in claim 2, further comprising: providing acompressor section, a turbine section, and a combustor section in thecore engine.
 4. The method as recited in claim 3, wherein the compressorsection is configured to drive a core flow through the core engine. 5.The method as recited in claim 1, further comprising: communicating anexhaust flow from the ECS pre-cooler or AOC “peaker” overboard of thegas turbine engine.
 6. The method as recited in claim 1, furthercomprising driving the bypass flow to the valve via a fan.
 7. The methodas recited in claim 1, wherein selectively positioning the valveincludes rotating the valve.
 8. The method as recited in claim 1,wherein selectively positioning the valve includes blocking bypass flowinto both the ECS pre-cooler and the AOC “peaker”.
 9. The method asrecited in claim 1, wherein the valve communicates the bypass flow intoeither the ECS pre-cooler or the AOC “peaker” via first and secondducts, respectively.
 10. The method as recited in claim 9, whereinselectively positioning the valve includes at least partially blockingbypass flow into at least one of the first and second ducts.
 11. Themethod as recited in claim 9, wherein selectively positioning the valveincludes fully blocking bypass flow into at least one of the first andsecond ducts.
 12. The method as recited in claim 1, wherein selectivelypositioning the valve is accomplished by a control system.